Well, no, both burns oppose the direction of orbital motion and reduce the instantaneous speed of the craft. the end rsult is faster motion that the start result, one of the seeming paradoxes of orbital mechanics.
you can do the same thing with a continuous thrust opposing oprbital motion, the result being a spiral orbit of decreasing altitude and increasing speed.
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separated by half an orbit, they would be, both are braking.
No, it's an instantaneous reduction in speed resulting in a lower orbit and thus a higher mean speed. (mean velocity is ofcourse zero)
An elliptical orbit trades speed for altitude (kinetic energy for gravitational potential) and vice-versa, if you increase speed at the low point it will result an an orbit that climbs higher.
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Acetylene is about the worst that easly had.
-- umop apisdn
t, but it takes orbital mechanics, rather than aerodynamics.
ially vector your solar sail to slow you down, converting your circular or bit into a more elliptical one that does get you closer to the sun, but if you want to end up in lower circular orbit, you've then got to vector the s ail to speed you up, because a closer-in circular orbit calls for a higher orbital velocity.
y with a solar sail. At best you might manage to _sloooowly_ spiral in.
more economical. The article does go on to talk about effecting orbital cha nges with low thrust ion drives. [...]
But - absent setting off nuclear explosions, Freeman Dyson style - a Hohman n manoeuvre is an infinite impulse ideal and nothing real is ever going to be a true Hohmnann manoeuvre. I was talking about orbital mechanics in gene ral, rather than a Hohmann manoeuvre, and cited the wikipedia article on Ho hmann manoeuvre's precisely because it had been extended to cover more real istic orbital transfer mechanisms.
two *braking* impulses and no speed ups.
ector, which does change with time - simply "dropping" into a lower orbit does increase your velocity, but not in the direction you need to make the lower orbit circular, so you need to apply the second episode of thrust in a direction which speeds up the satellite's tangential velocity while canc elling the in-falling velocity.
opposite to the direction of movement, at an instant where the radial velocity is nil. That's braking, in my book. Your last statement is wrong.
Half of it, anyway. The satellite in the lower orbit is travelling faster, even if the second impulse getting it into that orbit is in a counter-intui tive direction.
Sorry to be so slow to admit that you were right, but it has taken me a whi le to get my head around the counter-intuitive bit.
-- Bill Sloman, Sydney
z
acuum of space.
but it takes orbital mechanics, rather than aerodynamics.
lly vector your solar sail to slow you down, converting your circular orbi t into a more elliptical one that does get you closer to the sun, but if yo u want to end up in lower circular orbit, you've then got to vector the sai l to speed you up, because a closer-in circular orbit calls for a higher or bital velocity.
the instantaneous speed of the craft. the end result is faster motion that the start result, one of the seeming paradoxes of orbital mechanics.
An exceedingly counter-intuitive result.
gular posters - I initially typed "contributors", but thought better of it. "Detractors" would have come closer to the mark..
n, the result being a spiral orbit of decreasing altitude and increasing sp eed.
Even more counter-intuitive. Braking thrust that leaves you traveling faste r ...
-- Bill Sloman, Sydney
We're engineers, not mathematicians.
[...]No problem. Happens to me all the time.
Jeroen Belleman
Slowman, you're so full of yourself I bet your eyes are brown? If not, the infection from the excrement sitting behind them should be causing an incurable disease by now. Alzheimer, dementia etc..
I mean, the collateral damage won't be that high, since there isn't much up there to start with.
Jamie
- which is 172 generations ago. That's long enough that at least one of ou r ancestors probably lived there.
se your ancestors very carefully, and have failed to inherit the relatively sophisticated language processing mechanisms that most of us have - and yo u and krw obviously lack.
entually lose that chunk of your defective genetic machinery and replace it with something better.
e infection from the excrement sitting behind them should be causing an incurable disease by now. Alzheimer, dementia etc..
much up there to start with.
Amusing, coming from someone who isn't bright enough to make sense of what I post. Here's something else you will have trouble comprehending.
If you were just a little cleverer, you'd be aware that the brown pigment r esponsible for brown eye colour is melanin, which is not the pigment respon sible for the colour of excrement.
"Human feces ordinarily has a light to dark brown coloration, which results from a combination of bile and bilirubin that is derived from dead red blo od cells."
I rather doubt that you will be able to absorb this knowledge - the concept of a "pigment" is probably a little beyond you, and the idea that differen t pigments might have similar spectral behaviours would be a complication t hat you wouldn't want to bother with.
-- Bill Sloman, Sydney
It's clearly evident why you were and still are, unemployable..
Jamie
ote:
oes.
0 BC - which is 172 generations ago. That's long enough that at least one o f our ancestors probably lived there.choose your ancestors very carefully, and have failed to inherit the relati vely sophisticated language processing mechanisms that most of us have - an d you and krw obviously lack.
l eventually lose that chunk of your defective genetic machinery and replac e it with something better.
, the infection from the excrement sitting behind them should be causing an incurable disease by now. Alzheimer, dementia etc..
much up there to start with.
hat I post. Here's something else you will have trouble comprehending.
nt responsible for brown eye colour is melanin, which is not the pigment re sponsible for the colour of excrement.
ults from a combination of bile and bilirubin that is derived from dead red blood cells."
cept of a "pigment" is probably a little beyond you, and the idea that diff erent pigments might have similar spectral behaviours would be a complicati on that you wouldn't want to bother with.
It's clearly evident why you wouldn't want to employ me - you'd be afraid t hat I'd jeer at you, and that half the time you wouldn't be able to work ou t exactly why your colleagues were laughing at you.
Since I was thoroughly employable when younger, people smarter than you - a large group - would be able to work out that I only used my wit defensivel y, and got on fine with my colleagues, even the dimmer ones, though there w ere some resentful moments when I pointed out that one of their pet ideas w asn't going to work. That sometimes took some smoothing over.
-- Bill Sloman, Sydney
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